Modified lubricating oil



Patented Apr. 21, i942 MODIFIED LUBRECATING 01L David R. Merrill, Long Beach, char, assignor to Union Oil Qompany of California, Los Angeles, Calif a corporation of California No Drawing. Application December 23, 1938,

Serial No. 247,391 a 11 Claims.

stable against deterioration, as by oxygen and light, and when in use will overcome sticking of piston rings, valves and the like and the formation of sludges or sludge and lacquer deposits on the engine parts and will be-free from corrosive influences upon wrist pin bushings, crank shaft bearings and similar parts of such internal combustion engines, and will largely eliminate the formation of hard carbon behind piston rings.

Primarily the present invention resides in the employment in mineral lubricating oils of oilsoluble metal soaps of carboxylic acids, such as alkaline earth metal soaps or similar soaps of hydrogenated or partially hydrogenated rosin acids, especially where such soaps are used with a highboiling chlorinated aromatic compounds containing the chlorine in the ring, which compounds prevent formation of hard carbon behind piston rings, as behind the top ring. The group of materials which perform this latter function consists of such halogenated aromatics having boiling points of about 600 F. or somewhat higher, and which are adequately soluble in the oil (1. e. up to at least about 2%), of which chlorinated diphenyl and the higher chlorinated naphthalenes (tri, tetra, penta and hexa) or mix tures, are typical. The suitable oil-soluble soaps are soaps of carboxylic acids containing more than about ten carbon atoms per molecule, and exhibit a permanent state of solubility or dispersion in the lubricating oil as distinguished from soaps which tend to cloud or gel or stratify, at

rosin an'd rosin oil in smaller quantities than the abietic acid. This term and suitable equivalents will be explained more fully hereinafter.

More specifically, the invention may be said to reside in the employment in mineral lubricating oils of between about 1% and about 2% of an alkaline earth metal soap or similar oil-soluble soap of hydrogenated or partially hydrogenated rosin acids as above indicated, along with a small proportion of the indicated high boiling halogenated aromatics in the order of about 1% to about 2% orin quantity suflicient only approximately to overcome the formation of hard carbon as above mentioned. The invention further resides in the use of these materials in oils containing sulfur in substantial proportions, for instance, lubricating oils (distillates) naturally containing from around 0.5% or 1% to 6% or 7% of combined sulfur.

Preferably the lubricating oil will in any event be a naphthenic base mineral lubricating oil inasmuch as such oils in themselves possess some capacity to dissolve out or prevent the formation and deposition of gums and varnish or lacquerlike materials which tend to the sticking of rings and valves. I Therefore, the invention extends also to liquid lubricating oils where the mineral oil is of the naphthenic type.

Invention also resides in such oils with the indicated high boiling halogenated aromatics where using scans of the types indicated herein in amounts between about 0.75% and 2.5%. The invention also extends to the use of other appropriate oil-soluble carboxylic acid soaps in mineral oils with the high boiling chlorinated hydrocarbons hereof, such soaps including, for example,

calcium chloro stearates, 'calciumphenyl stearates,calciumnaphthenates, calciumsoaps of synleast in the proportions in which they are used for the present purposes. I have found that, where using the above mentioned soaps of hydrogenated or partially hydrogenated rosin acids alone, while the function is otherwise satisfactory to perform the desired functions and objects above mentioned, there is sometimes, nevertheless, a tendency for the formation of hard carbon around the upper ring or at the head of the piston, and that this dimculty can be overcome by adding small proportions of one of the high boiling halogenated aromatics indicated. By the term rosin acids is meant primarily abietic acid which ordinarily predominates in rosin and rosin oil, but the term is intended to include vkindred acids such as d-pimaric acid and the sapinic acids which are ordinarily present in thetic petroleum acids produced by the oxidation of petroleum fractionsas now known in the industry, corresponding oil-soluble magnesium and aluminum soaps of such carboxylic acids, and corresponding soaps of kindred acids such as the other fatty acids containing more than ten carbon atoms per molecule, for example oleic acid soaps, such acids being modified as by chlorination to render their soaps sumciently oil-soluble for the purposes herein indicated.

Preliminary In preparing soaps of hydrogenated abietic or rosin acids, which soaps are employed according to a preferred form of this invention, direct neutralization with a neutralizing material, such as calcium hydroxide,-may be employed; or esters of the hydroabietic acid, such as the methyl ester, may be employed and the calcium soap formed other desired soaps produced therefrom by metathesis. Inasmuch as esters,for example the methyl ester, of dihydroabietic acid are liquid, these materials are especially convenient of employment, but the invention is not limited thereto.

When employing approximately 1.25% to 1.50% of calcium soap of such hydrogenated rosin acids, highly efficient results have been obtained against the sticking of rings and valves and accumulations of resins, varnishes and the like in engine parts, and where sulfur has been incorporated, especially sulfur naturally occurring in the oils as herein indicated, corrosive tendencies by organic acids toward sensitive bearings, such as cadmium silver bearings, wrist pin bushings, and the like have also been overcome.

For the purpose of overcoming the indicated formation of hard carbon as sometimes accumulates behind the top ring of pistons and on other portions of the highly heated piston heads, small percentages, such as from about 1% to about 2%, or possibly within the range of about 0.5% to 3% to 4% of high boiling halogenated aromatic compounds herein-indicated having boiling points above about 600 F. and adequately oil-soluble in the percentages employed, are used. Such materials include halogenated diphenyl, halogenated diphenyl oxide and the more heavily halogenated naphthalenes such as tri-, tetra-, pentaand hexa-chloronaphthalenes which have boiling points between about 600 F. and '750" F., as above mentioned. So far as is known, all materials in this classification which have high heat stability and adequate solubility in the oil are useful for the present purpose. A particularly valuable item is chlorinated diphenyl oxide, which has a boiling point of around 700 F. and does not begin to give off chlorine as hydrogen chloride until about 680 F. The use of chlorinated diphenyl in amounts approximating 1% to 1.5% of the total composition has been found very effective. Specific classifications of suitable chlorinated aromatic compounds which may be used according to this invention are given hereinafter. I

Referring particularly to calcium soaps of hydrogenated rosin acids, or dihydroabietic acid, as preferred examples, such soaps are to be added to an otherwise satisfactory mineral lubricating oil in amounts ordinarily from about 1% to 2%. The mineral lubricating oil should in itself possess good solvent power for the soaps and pref! erably also possess appreciable solvent power for gums, resins, and varnishes which tend to form in heavy duty internal combustion engines or to accumulate in the oil from unburned or partially burned fuel residues, especially as in Diesel engines. 1

A desirable oil for average purposes is an ordinary California or naphthenic base mineral lubricating oil which in a typical case will have a natural sulfur content of about 0.5%. Where the final oil product is intended to be thoroughly non-corrosive, as where it is to be employed with highly corrosion-sensitive bearings such as cadmium silver bearings, the oil preferably should have a sufiicient or further ofisetting sulfur content to overcome any corrosive tendencies on the part of the soap such as might be generated in the oil during use as by hydrolysis of the soap or by reason of the presence of some constituent used in or with the soap. Such sulfur content also imparts additional oiliness and extreme pressure characteristics to the product, and 'it may be that such additional sulfur content exerts antioxidation effects upon the soap, because it has been observed that greater sulfur content (for example 2%) reduces the amount of deposits and produces softer deposits than smaller quantities such as 0.5% of sulfur- Such additional sulfur content may be very desirably obtained by employing a naphthenic base oil having a high natural sulfur content wherein organic sulfur compounds to the extent of a sulfur content of perhaps 3% to 4% on the oil remains after ordinary refining and acid treatment of the lubricating stock. Such high natural sulfur content naphthenic base oils are Santa Maria Valley (California) oils, Smackover (Arkansas) oils, Spindletop (Texas) oils and some Mexican oils. Again such high sulfur content oils may be combined with the above mentioned ordinary California or other naphthenic base lubricating oils to increase the sulfur content of the latter and blended in proportions from as low as 10% to as high as 50% or even approaching of the high sulfur oil so as to yield a total sulfur content of as low as about 1% upwards to 4% or even higher if possible. Increased sulfur content offsets corrosive tendency resulting from the soap or other addition agent, and as a result the oiliness and extremepressure characteristics will be greater. In addition to blending as indicated to increase the sulfur content, high sulfur content solvent extracts of lubricating oils may be added to oils deficient in sulfur. In the use of naphthenic oils of low sulfur content, as for example, 0.15% sulfur, the addition of some oil of high natural sulfur content has been found desirable to give a product of enhanced oiliness.

Definitions Dihydroabietic acid (C19H31COOH) may be taken as having the following probable structural formula:

COOH CH3 at t 6-01) The two hydrogens appearing in parentheses are the two hydrogens added to the abietic acid (CwHzoCOOH) the remaining double bond presumably having shifted to the position indicated. Chemists are not clear as to the exact formula for this compound but the above is believed to be the most probable structure in the light of present chemical knowledge. This formula is here advanced in order to describe in the most clear and full manner the nature of these materials but I do not desire to be limited thereto. The product of this invention, irrespective of its actual chemical composition, which forms the subject is produced as described below.

In employing hydrogenated rosin acids, such materials'may be either hydrogenated to the to abietic acid and produce the desired hydrogenated soaps of the present invention. -As is well known, rosin is the relatively high melting point residue obtained from the distillation of natural crude turpentine from living trees and known as gum rosin, or from the steam distillation or solvent extraction of the wood of pines and firs, such as cured or fatty pine stumps, and known as wood rosin. The turpentine passes oil? under low temperature distillation conditions to form gum turpentine when the exudate from the living tree is distilled, and to form wood turpentine when the products from old or cured wood are distilled. From these rosin residues left after the turpentine has been distilled ofi, normally liquid rosin oils may be distilled out in one or more fractions including redistillation if desired, leaving a still higher melting point gum' or wood rosin as the case may be.

The materials from wood distillation correspond generally with those from the living trees but differ in some particulars not clearly under-' stood. However all of these rosin oils and rosins contain abietic acids which may be used for the present purposes. Apparently the abietic acids which are distilled over in the rosin oils are of lower molecular weight than the polymers remaining in the rosin bottoms; or the diiferent abietic acids may be isomers of one another. The constitution above given for abietic acids is furnished as merely representative and there are undoubtedly many so-called abietic acids of varying constructions.

'It is generally understood that abietic acid as such does not exist in the natural secretions but that other constituents, possibly isomers, are present having about the same composition as abietic acid itself, namely C19H29COOH. In any event, heat treatment and also acid treatment yield abietic acid, and it would appear that heavier heat treatment yields various isomers of abietic acid and probably polymers thereof also. These acids, which are commonly referred to as abietic acid and are here. generally considered as consisting of abietic acid and its polymers principally but containing also d-pimaric and sapinic acids, are in general the acids intended when the term rosin acids is employed, this term including also the various isomers and polymers of these acids and kindred acids present in or obtainable from rosin. Inasmuch as all of these materals apparently are valuable for these purposes, it is, therefore, possible to saponify hydrogenated rosin or rosin oil and to use the entir product resulting, as well as to use soaps from the relatively pure segregated hydrogenated acids or esters. It is to be understood that wherethe acids are segregated, they are ordinarily hydrogenated after segregation, and that where rosin and rosin oils are employed, these materials are themselves hydrogenated. After hydrogenation of these materials, the soaps are then prepared. If esters of the hydrogenated acids are available starting material, these are first hydrolyzed, the acids recovered, and the soaps then produced by neutralization. In preparing such esters the hydrogenation may be effected either before or after esterification.

Operations As to operating procedures, mostof these are within the range of knowledge of the ordinary chemist skilled in the art, and inasmuch as much work has been done along these lines, detailed descriptions in some instances are not furnished. Briefly,- hydrogenation may be efiected in the presence of suitable hydrogenation catalysts such as platinum, and saponiflcation of the hydrogenated acids or the hydrogenated rosin or the hydrogenated rosin oil efiectedby heating the respective materials in the presence of the selected neutralizing material, of which calcium hydroxide as hereinbefore referred to is typical and'preferable. Where the mentioned, hydrogenated segregated acids or rosin or rosin oils are to be treated for formation of the soaps, such operations may take place under suitable heat conditions to effect liquidity in the presence of lubricating oil such as is to be used in the final product, or in the presence of other diluents, or otherwise as may be preferred or deemed desirable by the operating chemist. Where saponification of hydrogenated rosin and rosin oils with hydrated lime is effected in the presence of lubricating oil or other solvent, the eventual product is filtered for the removal of any solids, and the resultant concentrate is employed for addition to the preferred mineral base oil above described in such proportion as is required to yield the desired soap content in the final oil, namelybetween about 1% and 2%. Where soaps are to be formed from esters of hydrogenated rosin acids, as are now available on the market in the form of methyl esters under the trade name Hercolyn, the acids may be prepared therefrom as by hydrolysis with caustic alkali under rather severe conditions in the presence of a suitable solvent or diluent such as glycerin, whereby to form, for example, potassium dihydroabietate' which is treated with sulfuric acid whereby the dihydroabietic acid is freed and is then taken into solution in a solvent such as petroleum ether. A suitable soap, such as calcium soap, may then be prepared by heat-treating the recovered acids in the presence of lubricating oil with hydrated lime at elevated temperature to neutralize the acids, the solids being removedby filtration at an elevated temperature sufliciently high-to insure ready filtration.

.The various hydrogenating, esterifying and kindred reactions herein indicated may be effected in any known or preferred manner as will be apparent to the skilled chemist. Appropriate operations, especially for some of the less well known reactions, will be found described in the companion Humphrey Patents 1,877,179 and 2,099,066 for esterification with subsequent hydrogenation and for hydrogenation with subsequent esterification, respectively; Byrkit 1,973,865 and 2,094,117 for rosin hydrogenation; Butts 1,979,671 and 2,042,585 for hydrogenation of esters; Kaiser 2,074,963 for esterification; and similar patents. Also, corresponding materials may be bought on the open market.

Substitutes for calcium are preferably magnesium, zinc and aluminum, whose soaps may be employed where sufliciently soluble in the oil to be used. Other bases, where their soaps are sufficiently oil-soluble are sodium, potassium, manganese, tin and the like, and also organic bases may be imparted to the oil by sulfurizing or chlorinating an ester, such as methyl ester, of abietic acid, this agent being introduced for oiliness and/or non-corrosion purposes in addition to the soap. For these purposes about 0.25% to 3% of a sulfurlzed ester or a chlorinated ester or a sulfo-chlorinated ester may be used in addition to the 1% to 2% soap of the hydrogenated rosin acid.

In employing special sulfur-bearing oils here disclosed, the mentioned hydrogenated rosin acid soaps may be used in the Santa Maria Valley, Smackover and Spindletop oils mentioned which have high natural sulfur content; or they may be used in blends of such oils with other suitable naphthenic base oils such as the ordinary naphthenic base oils containing, for example 25% to 50% of high sulfur oil; or I may use such suitable ordinary naphthenic base oils to which have been added petroleum fractions of high sulfur content which may have been produced by distillation, solvent extraction, adsorption on active surfaces such as activated alumina or silica gel and the like, whereby products having a natural sulfur content of sufiicient degree are obtained. Such a-sulfur range may be between about 1% or less (such as 0.5%) and about 5% or according to requirements.

Inasmuch as the methyl ester of dihydroabietic acid is commercially available on the open market, such a material has been used as a starting material and the acids recovered by hydrolysis. As a specific example, a product now being produced by the Hercules Powder Company of Delaware is available under the trade name Hercolyn which is believed to be chiefly dihydromethyl-abietate. This material presents the following specifications:

Purity 92 94 Ester aee eea for five or six hours. Under these rather severe conditions, methyl alcohol distills ofi along with some water and a small amount of oily material, leaving a clear solution of potassium dihydroabietate in the glycerin with the excess potassium hydroxide. This mixture is dissolved in'about 3 gallons of water and then shaken up or otherwise agitated with about 2 partsof petroleum etherto wash out the unsaponified material, and the petroleum ether solution is removed. To the resultant water solution containing the soaps, an

excess of 1:1 or other dilute sulfuric acid'is added, whereby the water-insoluble free dihydroabietic acid separates. This free acid is then put into solution in'petroleum ether or similar light solvent, either by separating from the water solution and subsequently dissolving in the solvent, or by adding the petroleum light solvent to the water mixture, agitating thoroughly to effect solution of the dihydroabietic acid in the petroleum ether and removing the resultant supernatant layer of dihydroabietic acid solution by decantation from the lower layer or water solution containing the sulfuric acid and potassium sulphate. After washing the dihydroabietic acid solution with water, the light solvent is then distilled off at elevated temperature as by means of a slow stream of gas or otherwise. The resultant free dihydroabietic acid is-solid at normal temperatures, possesses an acid number between about 155 and 165 and Hanus iodine number which has been found to vary with different samples from 83.5 to as high as 110. The value of 110 in comparison with the theoretical figure of '84 may represent experimental error in the tester may indicate the presence of a limited proportion of unhydrogenated rosin acids.

Such dihydroabietic acid is dissolved in a small quantity of the petroleum lubricating oil to be used in the final product, employing temperatures of around 250 F. to effect solution. The resultant solution is then added to an additional quantity of the lubricating oil at about 120 F. in quantity sufficient to yield an eventual concentrate of about 7% to 10% soap. To this mixture about 15% to 20% of hydrated lime based on the acid present is added, along with about 0.1% we.-

ably is held as high as possible without causing Refractive index at 20 C 1.517 Specific gravity at 20/20 C 1.032 Acid number 5 Saponification number 24 Color (Lovibond-SO mm. tube) 5 amber Viscosity at 25 C 27 poise Flash point (Cleveland open cup) 183 C. Flame point (Cleveland open cup) 218 C. Vapor pressure (mm. Hg)

25 C Less than 0.01 100 C Less than 1.0 200 C 4 250 C 29 300 C 135 Boiling point 365-370 C.

and the mixture heated with stirring to about 300:F. and then up to around 320 F. to 340 F.

undesired darkening of the product, 275 F. representing the practical desirable limit. The temperature condition is maintained for about three to five hours or long enough to complete neutralization to the desired extent and the formation of calcium dihydroabietate. Upon completion of the saponification operation, the temperature is raised to about 325 F. to 350 F. and the mass sufficiently dehydrated to insure against any subsequent tendency to gel. This temperature also insures easy filtration, and the solids are filtered out through a filter precoated with a small quantity of any of the well known diatomaceous earth filter aids or the like, care being taken to avoid the use of filter aids either of character or in quantity sufilcient to effect removal of substantial amounts of the soap from the oil as by adsorption. The filtrate is then cooled and constitutes an oil-soap concentrate typically of around 7% to 10% soap content which is convenient for subsequent use inasmuch as its viscosity is not too high for convenient blending. The final blends are efiected merely by addition, at around 125 F. for example, of appropriate quantities of this concentrate to additional quantities of the selected mineral lubricating oil to yield a soap content of around 1.25% to 1.5% to cover the preferred range heretofore indicated.

Alternative to the above method of saponifying dihydroabietic acid in the presence of all of the oil desired in the concentrate, small proportions of oil may be used such as 1 or 2 volumes based on the acids, the acids being dissolved with heat as above indicated and the hydrated lime and indicated small proportion of water added and saponification effected directly at temperatures of around 275 F., the operation being continued until the desired extent .of saponification is effected. This results in a sort, of grease and by reason of the greater concentration, the saponification period is reduced substantially. In order to obtain from this grease-like mixture a suitable concentrate, additional oil is added to said mixture while hot and the temperature raised sufiiciently to eiTect dehydration, for example 325 F. to 350 F. This temperature also aids filtration which may be facilitated by the addition of a small percentage of diatomaceous earth which acts to assist separation of excess lime and to clarify the rosin derivatives. This hot product may be filtered through a precoated filter as above indicated, and the concentration of soap may be as high, if desired, as will permit convenient filtration at the indicated temperature. As an alternative to filtering in either of the instances above described, it may be possible to centrifuge the materials without the employment of diatomaceous earth or other filter aid. Similarly in both instances the presence of a free organic acidity in the final product (as hereinaiter stated) tends to make the soap-oil mixture more fluid and correspondingly further iacilitate filtration, this function of acid number being in addition to the stated stabilizing or solubilizing function of the free acid for the purpose of insuring soap retention in the presence of moisture, as hereinafter mentioned. All of these indicated concentrates are capable of subsequent dilution to the desired soap content of around 1% to 2% as previously indicated, such blending Water content In connection with preparation of these concentrates, the mentioned dehydration, to insure sumcient stability of products, preferably should be such that in a concentrate containing 40% soap the water content should be well under 1%, and a 7% concentrate should be dehydrated to a Water content of less than about 0.2%, in order that a final blend, such as one containing 1.33% soap, will have a water content well under 0.05%. Such low water content blends are resistant to elation and are still further resistant thereto when the final blend has an acid number of at least around 0.45, as discussed below.

Acid content For the preparation of a final blended oil for use in Diesel engines or other severe service internal combustion engines, it is preferable to employ a concentrate prepared as above described containing a calcium dihydroabietate (or similar-hydrogenated rosin acid soap of calcium or the like) possessing an acid number high enough that the final oil product shall have an acid number of at least about 0.45. By acid number is meant the amount of KOH in milligrams necessary to neutralize the acidity in one gram of the compounded product, and here refers to the A. S. T. M. method B for Compounded Petroleum Products" as distinguished from method A for Petroleum Products. These methods are found in the A. S. T. M. Standards for 1936, test number D188-27T described on pages 629 to 631.

Oils of this invention prepared with acid numbers of at least .4 to .45 according to said method B appear to be more stable than oils with low acid numbers, and the soaps are retained better in solution in the oil. Also such an acid number assures against the setting up of a gel (as above indicated) or consistent emulsion (e.i. emulsionhaving heavy consistency or exhibiting a yield point) during storage or shipping under such circumstances as may afford the presence of a small quantity of moisture. Thus, higher acid number increases the water tolerance. Ordinarily for Diesel engine and similar uses, an acid number of about 0.4 to 0.5 is preferable.

Such a desirable acid number may be obtained either by restricting the quantity of hydrated lime employed in the preparation of soap, or by limitin the heating time to eiIect the desired degree of saponification, or more conveniently by adding to a concentrate prepared with an excess of lime a suitably calculated quantity of dihydroabietic acid. Obviously the acid number can be suitably adjusted by either of these procedures or any other preferred method, such as the addition of small quantities of hydrogenated rosin or rosin oil.

Where hydrogenated rosin or hydrogenated rosin oil is to be used as the acidic material, this is dissolved in lubricating oil and saponifled with hydrated lime in substantially the same manner from the esters by hydrolysis.

solution in the oil along with the soap are retained and constitute a part of the product.

Chlorinated aromatics According to the present invention, there' is also added to the oil in addition to the soap, about 1% to 1.5% of a high boiling chlorinated aromatic compound, as above indicated, and further disclosed below, which material is readily incorporated along with the incorporation of the soap at the indicated temperatures. Such chlorinated aromatic compounds boil above about 600 F. and contain the chlorine in the aromatic ring," Preferably they should not be subject to appreciable decomposition to liberate chlorine at 450 F. These materials are covered by the following classification:

(I Hydrocarbons containing or consisting of a chlorinated aromatic or aryl nucleus;

(II) Neutral aromatic derivatives of the group consisting of ethers, ketones and esters which contain at least a chlorinated aryl or aromatic nucleus, and may also contain an alkyl radical or an aryl nucleus or a chlorinated aryl or aromatic nucleus or a hydrogenated aryl nucleus, or two or more of these, and

(III) Nitrogen-containing aromatics of the group consisting of nitriles and amines containing' a chlorinated aromatic nucleus.

Suitable examples of thesegroups, with their 320 c.-60s F.

di-naphthyl 380 C.716 F. V

II Neutral aromatic derivatives:

A. Ethers- Dichlor dibenzyl ether p-p' Dlchlor diphenyl ether Monochlor-naphth y l i s o a m yl ether B. Ketones- 2 Chlorobenzophenone 4 Chlorobenzophenone 4-4 Dichlorobenzophenone C. Esters- 2 Chlor phenyl benzoate Am yl 2, 3, 4

trichlor benzoate Monochlor-benzyl benzoate 330 C.-626 F.

. III Nitrogen-containing aromatics A. Aminesp Chlor phenylbenzylamine 315 C.599 F. Monochlor ditolylamine B. Nitriles- Dichlor na phthonitrile 'I'etrachlor benzylnitrile 310 C.-590 F.

Final oil product A typical final lubricating oil product for use in Diesel engines consists of a base lubricating oil containing about 1.33% of calcium soap of dihydroabietic acid produced as herein described, together with about 1.25% to 1.5% of chlorinated diphenyl or chlorinated naphthalene. v The S. A. E. 30 base oil may be a typical California or other typical naphthenic base mineral lubricating oil, or it may be such an oil blended with a quantity of S. A. E. 30 high sulfur naphthenic lubricating oil such as the Santa Maria Valley oil disclosed. Such a high sulfur oil blend may contaln from as little as 10% of Santa Maria Valley oil up to about 50% or even higher.

' The Santa Maria Valley S. A. E. 30 lubricating oil here employed was prepared by treatment with sixty pounds of 98% sulfuric acid per barrel and possesses the following characteristics:

- Santa Maria Valley S. A. E. 30 lubricating oil Gravity A. P. I. at 60 F. 19. 0 Viscosity index Color N. P. A 2. 4 Viscosity gravity con- 390 stant 345 C.653. F. I

It is to be noted that this oil contains a sulfur content of about 3.25%. If a lighter S. A. E. grade is used, the sulfur content will ordinarily be somewhat smaller, for example about 3% and if a heavier S. A. E. grade is used, the sulfur content will be somewhat greater, for example about 3.5%.

The typical California naphthenic base type S. A. E. 30 oil employed possesses the following characteristics:

Gravity A. P. I. at 60 F... 20.; viscotsity gravity con- Color N. P A an 0. Flash 0. O. C. PF 380 Sulfur by weight 0.5% Fire point C. O. C. "F 425 Indiana oxidation test: Viscosity at 100 F. Saybolt Hours for 10 mg. per 10 Universal 571.5 sec. gm. sample l5 Viscosity at 210 F. Saybolt Hours for 100 mg. per 10 Universal 55.3 sec. gm. sampl Pour point 5 F. Nil Acid number (method A). 0. 04 Carbon residue 0.10 Viscosity index 13 A typical S. A. E. 30 blend of the high sulfur Santa Maria oil and typical California naphthenic base oil above described consists of equal parts of each. Average test data for such a %-50% blend, with and without 1.33% calcium dihydroabietate and 1.5% chlorinated diphenyl containing about 65% chlorine, are given in the following table:

1.33%. With 1.33 o mum calcium .11? $2223? Without hydroabie- 1 5 o cmob soap ated diphenyl Gravity, A. P. I. at 60 F 19. 1 18. 6 19. 8

Viscosity, Saybolt Universal:

Seconds at 100 F. 689. 8 697. 1 550 Seconds at 210 F 58. 5 58.8 Viscosity index 11 15 Viscosity gravity constant.. 0.887 0. 891 0. 884 Flash, C. O. 6. F 370 385 370 Fire, 0. 0. G. F 445 440 445 Pour point 0 15 +5 Color, N. I. 4% 3% 3a Sulfated ash, percent by weight 0. 27 0. 29 N11 Sulfur by weight 1.88 1.88 1.88 Acid number (mg. KOH/g.) o. 45 3 .04

X By method B, t 1 By method A.

It is to be understood that each of the various soap-oil compositions here described is to contain between about 1% and about 2%. e. g. 1.5%. of one of the high boiling halogenated aromatic compounds having high temperature stability and high solubility in the lubricating oil, from the class herein described, and that the invention resides also in such oils containing aromatics of this class.

In manufacturing liquid mineral lubricating oils according to this invention, the high boiling halogenated aromatics here disclosed may be employed with other oil-soluble soaps including the light alkaline earth metal soaps (calcium and magnesium soaps) and soaps of the light metal aluminum, produced from other carboxylic acids than hydrogenated abietic acid, such as unmodifled rosin acids, fatty acids or chlorinated fatty acids having more than ten atoms to the molethe order of about three-fourths of 1% to 2.5% of an oil-soluble carboxylic acid soap in amount to overcome the formation of gummy and resinous materials tending to ring sticking in heavy service internal combustion engines, the oil also containing a small proportion of a chlorinated aromatic compound containing chlorine in the aromatic ring and boiling above about 600 F., in quantity suflicient to overcome the deposition of hard carbon behind piston rings, the oil being free from appreciable increase in viscosity over the original lubricating oil, the mineral oil possessing a natural combined-sulfur content of non-corrosive sulfur in excess of about 0.5%.

2. A mineral lubricating oil containing in the order of about three-fourths of 1% to 2.5% of an oil-soluble calcium soap of hydrogenated rosin acid, the amount of soap being sufiicient to substantially overcome the formation of gummy, resinous and varnish-like materials in severe service internal combustion engines and to overcome the sticking of piston rings and valve stems, the oil also containing between about 0.5% and about 2% of a chlorinated aromatic compound containing chlorine attached to the aromatic ring and boiling above about 600 F., and substantially free from decomposition to liberate chlorine at 450 F., and adapted to overcome deposition of hard carbon behind piston rings, the lubricating oil product being freely fluid at normal temperatures and free from grease-like characteristics and without appreciable increase in viscosity over that of the original lubricating oil, the oil naturally containing in excess of about 1% of combined sulfur.

3. A mineral lubricating oil containing between about three-fourths of 1% and 2.5% of an oilsoluble metal soap of carboxylic acid from the class of fatty acids of more than carbon atoms,

synthetic petroleum acids, naphthenic acids and the mineral oil being naphthenic base oil which naturally contains more than sulfur.

4. A mineral lubricating oil containing between about three-fourths of 1% and 2.5% of an oilsoluble calcium soap of a hydrogenated abietlc acid, and between about 1% and 2% of a about 0.5% of resinous and varnish-like materials and the sticking of valve stems and rings, and to overcome the deposit of hard carbon behind piston rings.

5. A lubricating 011 according to claim 4 wherein the soap is a calcium soap of a hydrogenated rosin acid. J

6. A mineral lubricating oil containing a small proportion of an oil-soluble metal soap of a hydrogenated rosin acid, sufiicient to overcome substantially the formation of gummy, resinous and varnish-like materials in severe service internal combustion engines and to overcome the sticking of piston rings and the like, the oil also containing a small proportion of a chlorinated aromatic compound boiling above 600 F. and substantially free from decomposition to liberate chlorine at 450 F. and adapted to control deposition of hard carbon about the pistons, the lubricating \oil product being substantially free from grease-like characteristics and without appreciable increase in viscosity over that of the original mineral lubricating oil.

7. An oil according to claim 6 wherein the'soap is a calcium soap of a hyrodrogenated rosin acid.

8. A mineral lubricating oil containing a small proportion of an oil-soluble metal soap of a saponifiable organic acid having more than about ten carbon atoms to the molecule, suflicient to chlorinated aromatic compound having a boiling point above about 600 F., the oil being liquid and adapted for use in severe service internal combustion engines to overcome deposition of gummy,

overcome substantially the formation of gummy, resinous and varnish-like materials in severe service internal combustion engines and to overcome the sticking of piston rings and the like, the oil also containing a small proportion of a chlorinated aromatic compound boiling above 600.F'. and substantially free from decomposition to liberate chlorine at 450 F. and adapted to control deposition of hard carbon about the pistons, the lubricating oil product being substantially free from grease-like characteristics and without I appreciable increase in viscosity over that of the original mineral lubricating oil, the mineral lubricating oil being a naphthenic base oil naturally containing organically combined noncorrosive sulfur in excess of about 0.5%.

9. An oil according to claim 8 wherein the soap isan oil-soluble metal soap of hydrogenated rosin acid.

10. A lubricant comprising mineral lubricating oil, a minor proportion of an oil-soluble soap of hydrogenated rosin acids in amount at least about three-quarters of one per cent, and minor proportion of chlorinated aromatic compound containing chlorine attached to the ring and boiling about 600 F. or over.

11. A lubricant according to claim 10 in which the mineral lubricating oil naturally contains in excess of about 0.5% of organically combined sulfur.

DAVID R. MERRILL. 

